Our studies have shown that in vitro methadone treatment of testes blocks the stimulatory effect of hCG on testosterone biosynthesis. The study designed here is to investigate whether methadone treatment in vivo also blocks the stimulatory effect of hCG. In addition, tissue endogenous cyclic AMP levels will be measured with and without methadone treatment. In another study the effect of exogenously added dibutyryl cyclic AMP on testosterone biosynthesis will be studied with and without methadone. It is also planned to study whether the effect of methadone is at the hypothalamic-pituitary level or at the peripheral receptor sites.